Stable and active oxidation catalysis by cooperative lattice oxygen redox on SmMn2O5 mullite surface

The correlation between lattice oxygen (O) binding energy and O oxidation activity imposes a fundamental limit in developing oxide catalysts, simultaneously meeting the stringent thermal stability and catalytic activity standards for complete oxidation reactions under harsh conditions. Typically, strong O binding indicates a stable surface structure, but low O oxidation activity, and vice versa. Using nitric oxide (NO) catalytic oxidation as a model reaction, we demonstrate that this conflicting correlation can be avoided by cooperative lattice oxygen redox on SmMn2O5 mullite oxides, leading to stable and active oxide surface structures. The strongly bound neighboring lattice oxygen pair cooperates in NO oxidation to form bridging nitrate (NO3–) intermediates, which can facilely transform into monodentate NO3– by a concerted rotation with simultaneous O2 adsorption onto the resulting oxygen vacancy. Subsequently, monodentate NO3– species decompose to NO2 to restore one of the lattice oxygen atoms that act...